Lock-up clutches, in hydrodynamic torque converters, are used to directly connect the input shaft of the hydrodynamic torque converter to its output shaft, which creates a direct throughdrive of the drive motor to the downstream transmission and can improve the efficiency of the overall system.
DE 4030811 A1 discloses a method for controlling a lock-up clutch of a hydrodynamic torque converter that is controlled to bring the lock-up clutch into a state of slippage depending on the change of the engine load, wherein a specific degree of slippage is set.